Blood transports substances like digested food from the small intestine to the other parts of the body. It carries oxygen from the lungs to the cells of the body. It also transports waste for removal from the body. So, it acts as a carrier of various substances. Every part of the body needs certain substances to perform its functions. Additionally, every part creates some waste products for removal. Blood is needed by all parts of the body so that various substances can be supplied to them and waste can be removed from them.
